Recently, electric powered vehicles with a power storage device (e.g., a secondary battery or a capacitor) mounted thereon and running through use of driving force generated from electric power stored in the power storage device are receiving attention as environmentally friendly vehicles. Such electric powered vehicles include, for example, electric vehicles, hybrid vehicles, fuel cell vehicles, and the like.
Such electric powered vehicles may include a motor generator for generating driving force for running upon receiving electric power from the power storage device at the time of starting or acceleration, and generating power by regenerative braking at the time of braking to store electric energy in the power storage device. In order to control the motor generator in accordance with the state of running as described above, a power conversion device such as a converter or an inverter is mounted on an electric powered vehicle.
Such a power conversion device includes a large-capacity smoothing capacitor in order to stabilize supplied DC power. During operation of the power conversion device, charge in accordance with an applied voltage is stored in the smoothing capacitor.
As to the charge stored in the smoothing capacitor, it is necessary to discharge residual charge in the smoothing capacitor rapidly, in such a case where a collision of a vehicle has occurred.
Japanese Patent Laying-Open No. 2004-201439 (PTL 1) discloses a technique for controlling a converter to perform a boosting operation and a step-down operation alternately when supply of DC power is stopped in a voltage conversion system including smoothing capacitors provided at the input side and the output side of the converter capable of the boosting operation and the step-down operation, thereby consuming residual charge stored in the smoothing capacitors.